2 * drivers/input/touchscreen/tsc2007.c
4 * Copyright (c) 2008 MtekVision Co., Ltd.
5 * Kwangwoo Lee <kwlee@mtekvision.com>
9 * Copyright (c) 2005 David Brownell
10 * Copyright (c) 2006 Nokia Corporation
12 * Copyright (C) 2004-2005 Richard Purdie
13 * - omap_ts.[hc], ads7846.h, ts_osk.c
14 * Copyright (C) 2002 MontaVista Software
15 * Copyright (C) 2004 Texas Instruments
16 * Copyright (C) 2005 Dirk Behme
18 * This program is free software; you can redistribute it and/or modify
19 * it under the terms of the GNU General Public License version 2 as
20 * published by the Free Software Foundation.
23 #include <linux/module.h>
24 #include <linux/slab.h>
25 #include <linux/input.h>
26 #include <linux/interrupt.h>
27 #include <linux/i2c.h>
28 #include <linux/i2c/tsc2007.h>
29 #include <linux/of_device.h>
30 #include <linux/of_gpio.h>
33 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
38 data = i2c_smbus_read_word_data(tsc->client, cmd);
40 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
44 /* The protocol and raw data format from i2c interface:
45 * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
46 * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
48 val = swab16(data) >> 4;
50 dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
55 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
57 /* y- still on; turn on only y+ (and ADC) */
58 tc->y = tsc2007_xfer(tsc, READ_Y);
60 /* turn y- off, x+ on, then leave in lowpower */
61 tc->x = tsc2007_xfer(tsc, READ_X);
63 /* turn y+ off, x- on; we'll use formula #1 */
64 tc->z1 = tsc2007_xfer(tsc, READ_Z1);
65 tc->z2 = tsc2007_xfer(tsc, READ_Z2);
67 /* Prepare for next touch reading - power down ADC, enable PENIRQ */
68 tsc2007_xfer(tsc, PWRDOWN);
71 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc)
76 if (tc->x == MAX_12BIT)
79 if (likely(tc->x && tc->z1)) {
80 /* compute touch resistance using equation #1 */
83 rt *= tsc->x_plate_ohms;
85 rt = (rt + 2047) >> 12;
91 bool tsc2007_is_pen_down(struct tsc2007 *ts)
94 * NOTE: We can't rely on the pressure to determine the pen down
95 * state, even though this controller has a pressure sensor.
96 * The pressure value can fluctuate for quite a while after
97 * lifting the pen and in some cases may not even settle at the
100 * The only safe way to check for the pen up condition is in the
101 * work function by reading the pen signal state (it's a GPIO
102 * and IRQ). Unfortunately such callback is not always available,
103 * in that case we assume that the pen is down and expect caller
104 * to fall back on the pressure reading.
107 if (!ts->get_pendown_state)
110 return ts->get_pendown_state(&ts->client->dev);
113 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
115 struct tsc2007 *ts = handle;
116 struct input_dev *input = ts->input;
120 while (!ts->stopped && tsc2007_is_pen_down(ts)) {
122 /* pen is down, continue with the measurement */
124 mutex_lock(&ts->mlock);
125 tsc2007_read_values(ts, &tc);
126 mutex_unlock(&ts->mlock);
128 rt = tsc2007_calculate_resistance(ts, &tc);
130 if (!rt && !ts->get_pendown_state) {
132 * If pressure reported is 0 and we don't have
133 * callback to check pendown state, we have to
134 * assume that pen was lifted up.
139 if (rt <= ts->max_rt) {
140 dev_dbg(&ts->client->dev,
141 "DOWN point(%4d,%4d), resistance (%4u)\n",
144 rt = ts->max_rt - rt;
146 input_report_key(input, BTN_TOUCH, 1);
147 input_report_abs(input, ABS_X, tc.x);
148 input_report_abs(input, ABS_Y, tc.y);
149 input_report_abs(input, ABS_PRESSURE, rt);
155 * Sample found inconsistent by debouncing or pressure is
156 * beyond the maximum. Don't report it to user space,
157 * repeat at least once more the measurement.
159 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
162 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
165 dev_dbg(&ts->client->dev, "UP\n");
167 input_report_key(input, BTN_TOUCH, 0);
168 input_report_abs(input, ABS_PRESSURE, 0);
171 if (ts->clear_penirq)
177 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
179 struct tsc2007 *ts = handle;
181 if (tsc2007_is_pen_down(ts))
182 return IRQ_WAKE_THREAD;
184 if (ts->clear_penirq)
190 static void tsc2007_stop(struct tsc2007 *ts)
196 disable_irq(ts->irq);
199 static int tsc2007_open(struct input_dev *input_dev)
201 struct tsc2007 *ts = input_get_drvdata(input_dev);
209 /* Prepare for touch readings - power down ADC and enable PENIRQ */
210 err = tsc2007_xfer(ts, PWRDOWN);
219 static void tsc2007_close(struct input_dev *input_dev)
221 struct tsc2007 *ts = input_get_drvdata(input_dev);
227 static int tsc2007_get_pendown_state_gpio(struct device *dev)
229 struct i2c_client *client = to_i2c_client(dev);
230 struct tsc2007 *ts = i2c_get_clientdata(client);
232 return !gpio_get_value(ts->gpio);
235 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
237 struct device_node *np = client->dev.of_node;
242 dev_err(&client->dev, "missing device tree data\n");
246 if (!of_property_read_u32(np, "ti,max-rt", &val32))
249 ts->max_rt = MAX_12BIT;
251 if (!of_property_read_u32(np, "ti,fuzzx", &val32))
254 if (!of_property_read_u32(np, "ti,fuzzy", &val32))
257 if (!of_property_read_u32(np, "ti,fuzzz", &val32))
260 if (!of_property_read_u64(np, "ti,poll-period", &val64))
261 ts->poll_period = msecs_to_jiffies(val64);
263 ts->poll_period = msecs_to_jiffies(1);
265 if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
266 ts->x_plate_ohms = val32;
268 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
272 ts->gpio = of_get_gpio(np, 0);
273 if (gpio_is_valid(ts->gpio))
274 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
276 dev_warn(&client->dev,
277 "GPIO not specified in DT (of_get_gpio returned %d)\n",
283 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
285 dev_err(&client->dev, "platform data is required!\n");
290 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
291 const struct tsc2007_platform_data *pdata,
292 const struct i2c_device_id *id)
294 ts->model = pdata->model;
295 ts->x_plate_ohms = pdata->x_plate_ohms;
296 ts->max_rt = pdata->max_rt ? : MAX_12BIT;
297 ts->poll_period = msecs_to_jiffies(pdata->poll_period ? : 1);
298 ts->get_pendown_state = pdata->get_pendown_state;
299 ts->clear_penirq = pdata->clear_penirq;
300 ts->fuzzx = pdata->fuzzx;
301 ts->fuzzy = pdata->fuzzy;
302 ts->fuzzz = pdata->fuzzz;
304 if (pdata->x_plate_ohms == 0) {
305 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
312 static void tsc2007_call_exit_platform_hw(void *data)
314 struct device *dev = data;
315 const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
317 pdata->exit_platform_hw();
320 static int tsc2007_probe(struct i2c_client *client,
321 const struct i2c_device_id *id)
323 const struct tsc2007_platform_data *pdata =
324 dev_get_platdata(&client->dev);
326 struct input_dev *input_dev;
329 if (!i2c_check_functionality(client->adapter,
330 I2C_FUNC_SMBUS_READ_WORD_DATA))
333 ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
338 err = tsc2007_probe_pdev(client, ts, pdata, id);
340 err = tsc2007_probe_dt(client, ts);
344 input_dev = devm_input_allocate_device(&client->dev);
348 i2c_set_clientdata(client, ts);
351 ts->irq = client->irq;
352 ts->input = input_dev;
354 init_waitqueue_head(&ts->wait);
355 mutex_init(&ts->mlock);
357 snprintf(ts->phys, sizeof(ts->phys),
358 "%s/input0", dev_name(&client->dev));
360 input_dev->name = "TSC2007 Touchscreen";
361 input_dev->phys = ts->phys;
362 input_dev->id.bustype = BUS_I2C;
364 input_dev->open = tsc2007_open;
365 input_dev->close = tsc2007_close;
367 input_set_drvdata(input_dev, ts);
369 input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
371 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
372 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
373 input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
377 if (pdata->exit_platform_hw) {
378 err = devm_add_action(&client->dev,
379 tsc2007_call_exit_platform_hw,
382 dev_err(&client->dev,
383 "Failed to register exit_platform_hw action, %d\n",
389 if (pdata->init_platform_hw)
390 pdata->init_platform_hw();
393 err = devm_request_threaded_irq(&client->dev, ts->irq,
394 tsc2007_hard_irq, tsc2007_soft_irq,
396 client->dev.driver->name, ts);
398 dev_err(&client->dev, "Failed to request irq %d: %d\n",
405 /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
406 err = tsc2007_xfer(ts, PWRDOWN);
408 dev_err(&client->dev,
409 "Failed to setup chip: %d\n", err);
410 return err; /* chip does not respond */
413 err = input_register_device(input_dev);
415 dev_err(&client->dev,
416 "Failed to register input device: %d\n", err);
420 err = tsc2007_iio_configure(ts);
422 dev_err(&client->dev,
423 "Failed to register with IIO: %d\n", err);
430 static const struct i2c_device_id tsc2007_idtable[] = {
435 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
438 static const struct of_device_id tsc2007_of_match[] = {
439 { .compatible = "ti,tsc2007" },
442 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
445 static struct i2c_driver tsc2007_driver = {
448 .of_match_table = of_match_ptr(tsc2007_of_match),
450 .id_table = tsc2007_idtable,
451 .probe = tsc2007_probe,
454 module_i2c_driver(tsc2007_driver);
456 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
457 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
458 MODULE_LICENSE("GPL");